It can be used to create a custom error message .

Example

<?php
$val=2;
if ($val>1)trigger_error(“A custom error has been triggered”);
?>

It sets a user-defined function to handle exception

Example

<?php
function customException($exception){
echo  $exception->getMessage();
}
set_exception_handler(‘customException’);
throw new Exception(‘Uncaught Exception occurred’);
?>

Output

Exception: Uncaught Exception occurred

It sets a user-defined function to handle errors

Example

<?php
function errorFunc($errno, $errstr, $errfile, $errline) {
echo $errstr.” on ” . $errfile .” at “. $errline;
}
set_error_handler(“errorFunc”);
$val=5;
if ($test>1)  trigger_error(“An error occured”);
?>

Output

Undefined variable: test on /var/www/test/index.php at 7

It r restores the previous exception handler

Example

<?php

function customError($errno, $errstr, $errfile, $errline)  {
echo $errno.””.$errstr.” , File name – “.$errfile.” at line No”.$errline;
}

set_error_handler(“customError”);

$val=5;

if ($val>1)  trigger_error(“An error occured”);

restore_error_handler();

if ($val>5)  trigger_error(“An error occured”);

?>

Output

exception_handler_1 – This triggers the first exception handler…

It restores the previous error handler

Example

<?php

function customError($errno, $errstr, $errfile, $errline)  {
echo $errno.””.$errstr.” , File name – “.$errfile.” at line No”.$errline;
}

set_error_handler(“customError”);

$val=5;

if ($val>1)  trigger_error(“An error occured”);

restore_error_handler();

if ($val>5)  trigger_error(“An error occured”);

?>

Output

1024An error occured , File name – /var/www/test/date/date.php at line No11

It specifies which errors are occurred.

Example

<?php
error_reporting(E_ALL);
?>

E_ERROR ,E_WARNING,E_PARSE,E_NOTICE,E_CORE_ERROR,E_CORE_WARNING ,E_COMPILE_ERROR,E_COMPILE_WARNING,E_USER_ERROR,E_USER_WARNING,E_USER_NOTICE,E_STRICT ,E_RECOVERABLE_ERROR,E_ALL

Output

It shows all the errors occurred including waring,notice etc

It sends an error to the server error-log

<?php
$value=2;
if ($value>1){
error_log(“An error occured”,1,”info@phpcodez.com”,”From: from@phpcodez.com”);
}
?>

Error  message will be sent to the given  email address

It returns the last error occurred

Example

<?php
echo “<pre>”;
echo $test;
print_r(error_get_last());
?>

Output

Array
(
[type] => 8
[message] => Undefined variable: test
[file] => /var/www/test/index.php
[line] => 3
)

It prints a backtrace

Example

<?php
echo “<pre>”;
function back($arg1, $arg2) {
debug_print_backtrace();
}
back(“test1”, “test2”);
?>

Output

#0  back(Peter, Griffin) called at [/var/www/test/index.php:6]

It generate a generates a backtrace and displays data from the code that led up to the debug_backtrace() function.

<?php
echo “<pre>”;
function back($arg1, $arg2) {
print_r(debug_backtrace());
}
back(“test1”, “test2”);
?>

The possible elements that can be returned are given below

function,line,file,class,object,type,Returns: “->” ,Returns: “::” ,Returns nothing,args

Output

Array
(
[0] => Array
(
[file] => /var/www/test/index.php
[line] => 6
[function] => back
[args] => Array
(
[0] => Peter
[1] => Griffin
)

)

)